As the planet warms, air conditioning is becoming a critical necessity in much of the world. But common AC technologies have an outsized climate impact, driving temperatures even higher. CLASP, an international NGO, dives deeper into this topic.
Ana Maria Carreño has spent years working to disrupt this cycle. As CLASP’s senior director of climate, she identifies and implements solutions for keeping people cool without heating up the planet. In this interview with CLASP’s Sarah Wesseler, she discusses AC’s mitigation challenges and what it would take to solve them.
Sarah Wesseler: The links between climate change and air conditioning have been widely covered in the media. It’s a complex problem, though, and I suspect most climate advocates don’t have a nuanced understanding of it, let alone a sense of how to solve it. What do you see as the most important things to understand about reducing emissions from ACs?
Ana Maria Carreño: Well, first of all, you have to reduce the demand for artificial cooling. But that doesn’t mean asking people to live with excess heat. Instead, it means changing the way we design cities and buildings.
If you look at places built before modern HVAC [heating, ventilation, and air conditioning] equipment was invented, they’re highly responsive to their local climates. In hot places, design solutions like shade and natural ventilation kept people comfortable even during the summer. Things like large porches, internal courtyards, and trees kept direct sunlight out of building interiors, for example. Even something as simple as light-coloured roofs that reflect heat away from buildings can make a huge difference.
Today, a lot of this nuance has been lost. You can find essentially the same types of buildings and neighbourhoods being built in very different climates, which leads to unnecessarily huge air conditioning loads. It also means more heating is needed in the winter, but that’s another story.
So ,we need to go back to this older model of working with local environmental conditions to create places that are comfortable in hot weather even without air conditioning.
There’s a lot of really interesting work happening on this front. For example, in Colombia, where I’m from, the city of Medellín has had a lot of success in reducing heat by planting trees on busy streets to create shade. The program has really made a difference, lowering local temperatures by 2º degrees Celsius (3.6º Fahrenheit).
So, reducing the demand for mechanical cooling is the first step. And then once we get that as low as it can go, we need to meet the remaining demand in a way that’s as climate-friendly as possible. That means paying close attention to electricity and refrigerants, which are the two main sources of emissions.
The electricity emissions come from burning fossil fuels in places where the electricity used by ACs is produced with oil, gas, or coal. Because a lot of electricity is produced this way, ACs are indirectly responsible for a large volume of emissions. That’s why it’s important to use efficient equipment. As we reduce the amount of energy needed to run ACs, we can reduce the amount of fossil fuels burned.
Refrigerants are also really important. They’re classified in terms of their global warming potential, which is extremely high for some refrigerants. One of the most common ones used in air conditioners, R-410A, is 2,000 times more potent than carbon dioxide.
The world is moving away from refrigerants that have high global warming potential, but that transition is not happening as fast as it should. The transition is being driven by commitments many countries made under the Kigali Amendment of the Montreal Protocol to phase down and phase out these refrigerants. But national regulations are needed to speed the process, and in many countries, there is no regulation.
Wesseler: OK, so electricity use and refrigerants make ACs problematic from a climate perspective. How problematic, specifically? How much of a climate risk does AC pose?
Carreño: Well, data from CLASP’s appliance efficiency policy model, Mepsy, show that the projected emissions in 2030 from room air conditioners alone – so not counting any other type of space cooling, like fans – are about 800 megatons, which is almost a gigaton. That’s roughly equivalent to driving 186 million gasoline-powered cars for a year.
We’ve also found that, to achieve net-zero scenarios by 2050, emissions from the entire appliance sector need to fall by nine gigatons by 2050. So, when you consider that room air conditioners will reach one gigaton of emissions in 2030, that tells you the magnitude of the challenge AC poses for the climate community.
What makes this even more difficult is that, at the same time that we need to reduce emissions from AC, we need to help more people get access to air conditioners.
For many years, the efficiency community talked about air conditioners being a luxury – something that was only for households with the capacity to purchase the equipment and pay high electricity bills. But now summers are becoming so hot in many places that it’s almost impossible to stay healthy, to work, to study without AC. But there’s still very low access to air conditioning in Southeast Asia, Latin America, and Africa.
Brazil is a good example. Only 20% of households there own an air conditioner—most people use fans for cooling since they’re cheaper than AC. But the summers are becoming hotter and hotter. This year, the temperature reached 44° Celsius (111° Fahrenheit) in Rio de Janeiro. In heat like that, fans are no longer enough to keep people cool.
Brazil actually set a new record for air conditioner sales in 2024 because of the growing heat. There were six million new ACs sold, which is a 38% increase from 2023.
This same kind of growth is happening in other countries as well. The IEA (International Energy Agency) has forecast that demand for cooling will triple by 2050.
**Read the full interview on the CLASP website. Click here.